Missing Malaysian airlines flight crash
Vietnamese military officer Duong Van Lanh looks out a window while working onboard a Vietnamese airforce AN-26 during a mission to find the missing Malaysia Airlines flight MH370 off Tho Chu islands  - Reuters

Vietnam has partially suspended its search and rescue mission to find the missing Malaysia Airlines jet MH370, frustrated over an alleged lack of response from Malaysian authorities.

Scaling back its operations, Vietnam has said it will recall ships involved in the search.

"We've decided to temporarily suspend some search and rescue activities, pending information from Malaysia," Vietnam's deputy transport minister Pham Quy Tieu, who is leading the search operations, told reporters.

"We still have plans to search with a few flights today, while other activities are suspended."

He said Malaysian authorities are yet to respond to repeated requests from Vietnamese officials regarding key information about the search measures.

Meanwhile, Malaysia has said it is extending search operations to the Andaman Sea, hundreds of miles from the original search radius.

"Yes, above Sumatra is the Andaman Sea," Malaysian civil aviation chief Azharuddin Abdul Rahman told AFP, when asked about the plans.

"We are not going to leave any chance. We have to look at every possibility."

It is still unclear whether the authorities have found any clues to trace the Boeing 777 to that region.

Air force chief's denial

Meanwhile, Malaysia's air force chief has denied reports that quoted him as saying the military radar had tracked the jetliner over the Strait of Malacca.

Rubbishing the reports, Air Force chief Rodzali Daud said in a statement: "I wish to state that I did not make any such statements.

"What occurred was that the Berita Harian journalist asked me if such an incident occurred as detailed in their story. However, I did not give any answer to the question.

"Instead, what I said to the journalist was, 'Please refer to the statement which I made on 9 March 2014, during the press conference with the Chief of Defence Forces at the Sama-Sama Hotel, Kuala Lumpur International Airport'."

The pro-government local daily Berita Harian had earlier quoted the official as saying: "The last time the plane was detected by the air control tower was in the vicinity of Pulau Perak in the Straits of Malacca at 2.40 in the morning before the signal disappeared without any trace."

The whereabouts of the Kuala Lumpur-Beijing flight, with 239 people on board still remains a mystery more than 90 hours after its disappearance and no clues have yet been found to trace the jetliner.